The present invention relates to a fuel injection valve suitable for injecting fuel into an automobile engine.
Heretofore, as a fuel injection valve used for an automobile engine, there is known one that incorporates a nozzle plate with a plurality of nozzles opened therein, on the downstream side of the valve seat (refer to Japanese Unexamined Patent Publication No. 7-127550).
Incidentally, in the above mentioned fuel injection valve which incorporates the nozzle plate, the smaller the diameter of the nozzles, the more the fuel is atomized. Therefore, it is preferable to make the diameter of the nozzles as small as possible.
However, there is a manufacturing limit to the minimum diameter for the nozzles. Moreover, if the diameter of the nozzles is too small, the nozzles are likely to be clogged.
Therefore, there has so far been the problem in that it is difficult to make the diameter of the nozzles even smaller to promote atomization of the fuel.
It is therefore an object of the present invention to provide a fuel injection valve of a construction wherein the outer diameter of a jet passing through the nozzle can be contracted, so that atomization of fuel can be promoted without reducing the diameter of the nozzle.
In order to achieve the above object, according to the present invention, a nozzle plate with a plurality of nozzles opened therein is provided with annular step portions each located on the periphery of a nozzle opening rim on a valve seat side, which rises up towards the nozzle opening rim from the radial outside of the nozzle, to form a fuel flow which flows in reverse from the radial outside to collide at an incline with a fuel flow which flows directly into the nozzle.
The other objects and features of this invention will become understood from the following description with reference to the accompanying drawings.